\[\frac{1}{f}=\frac{1}{p}+\frac{1}{q}\]
Variables
ffocal length (m)
pobject distance (m)
qimage distance (m)
Description
What is this formula?
This formula relates the focal length of a spherical mirror with the object distance and image distance. The variables p and q are commonly used in geometrical optics for mirror systems and determine where the reflected image forms.
When to use it
Use this formula when analyzing concave and convex mirrors, reflective optical instruments, and image formation.
Example
Given:
p=0.40 m
f=0.15 m
Formula:
1/f=1/p+1/q
Rearranged:
q=(f×p)/(p−f)
Substitution:
q=(0.15×0.40)/(0.40−0.15)
Result:
q=0.24 m
Applications
- Telescope mirrors
- Vehicle mirrors
- Reflective optical systems
- Image formation
- Optical instruments